This invention relates to a shielding apparatus which will reduce leakage of undesirably generated electromagnetic waves, and which provides insulation from the influence of external noise. More particularly, this invention relates to an insulating box or casing of an electronic device.
Recent advances in electronics technology have led to an increase in the use of computers and other digital electronic devices. In turn, this has led to problems resulting from electromagnetic interference, primarily caused by the leakage of electromagnetic waves from electronic devices.
In order to prevent electromagnetic interference, it is necessary to fully cover a device which emits electromagnetic radiation with a casing which is made of a shielding material and is joined without seams. Metal plates are conventionally used as a suitable material, but are detrimental in that they may be difficult to shape into a specified form. In practice, moreover, it is preferable that a casing can easily be detached for maintenance purposes. Furthermore, using conventional methods, the emission of electromagnetic radiation from certain parts of a device, for example switches, connectors, air vents and display screens, cannot be fully shielded.
When a device is to be enclosed within a molded plastic casing, the type of casing known in the prior art provides for plating the device with metal on an internal surface of the casing, or otherwise applying a suitable coating for effective electromagnetic shielding. This type of electromagnetic shielding may be insufficient.
It is difficult to treat a display screen for electromagnetic shielding using conventional techniques, and therefore the leakage of electromagnetic waves often cannot be reduced below a certain level. However, as the number of electronic devices increases, the allowable leakage per device inevitably becomes restricted.
This invention aims to solve these problems encountered in the prior art, and to provide a casing suitable for use on an electronic device which can significantly reduce leakage of electromagnetic waves. Thus, the invention may be used to substantially reduce electromagnetic interference which may otherwise cause problems in the area surrounding an electromagnetic device.